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Iletin I Lente
Eli Lilly's old product --an 85%% bovine, 15% porcine lente insulin which is intermediate-acting. Current nearest equivalents are: Hypurin Bovine Lente by CP Pharma and Betasint Bovine Lente by Beta Laboratorios. It shared the Lente composition definition of being a suspension of crystalline (ultralente) and amorphous (semilente) insulin in a ratio of 7 crystalline parts to 3 amorphous parts. Why Lente doesn't equal 70/30 Let's look at the differences in the two insulins. Lente is comprised of 70 % long-acting Ultralente insulin and 30% short-acting Semilente insulin. So proportions of a long-acting and short-acting insulin are being combined to produce a intermediate-acting insulin. Both Ultralente and Semilente insulin are suspended by adding zinc and the size of their respective insulin crystals. The largest insulin crystals are those of Ultralente, while Semilente contains the smallest, or microcrystals. Simply put, you're combining a long insulin and a short insulin to make an intermediate-acting one. 70/30 insulin starts with 70% NPH/isophane insulin, an intermediate-acting insulin which is suspended by protamine. To that, 30% R/neutral/normal insulin, which is short-acting and soluble, meaning there is no suspension; nothing is added to this insulin to delay its action. In this case, you are taking an intermediate-acting insulin with a suspension and adding to it a short-acting one with no suspension to create an intermediate-acting insulin. So we have an insulin (Lente), made up of a long-acting and short-acting insulin, both with zinc suspensions, and a mixed insulin (70/30), made from an intermediate-acting protamine suspended insulin and a short-acting one without any suspension. Because of these differences, the insulin action profile for these two insulins is going to be quite different, even though both insulins are classed as intermediate-acting. What Lente Is Not No Lente-type insulin regardless of species can contain any NPH/isophane insulin or any R/Neutral insulin. Both are chemically impossible: the phenol preservative present in NPH/isophane alters the action of Lente-type insulins, creating a mixture with an approximate action of R/Neutral. The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. Note--in 1980, there were no r-DNA/GE/GM insulins Before the invention of VetPen, Lente-type insulins could not be dispensed in pen or cartridge form because the glass ball formerly used to mix the insulin in these devices shattered the Lente crystals. Combining Lente Family Insulins Insulin manufacturers indicate that R/neutral and semilente, Lente, ultralente insulins are able to be combined in the same syringe, but only just before injection. In pre-filled syringes, the zinc suspension of the Lente-type insulins binds the R/neutral, causing it to lose its short-acting effect. Various studies have documented this, and some doctors advise against using R/neutral in the same syringe with the Lente family of insulins. The following are lente type zinc suspension insulins but since they are produced for use in animals, they are not found in BNF, but in its sister veterinary formulary. These fall into the category of intermediate-length insulins. The blended beef/pork Iletin I was produced until 1999. References More information *Insulin therapy for dogs and cats Dowling, Patricia, September 1995, Canadian Veterinary Journal A discussion of Iletin insulins. *Lente Insulins-Injectable Suspensions West Virginia University College of Pharmacy-2009 Related pages Category:Insulins Category:Bovine Category:intermediate-acting Category:Eli Lilly Category:Intravenous use NO Category:Methylparaben Category:Zinc Category:Acetate Category:Content Category:Porcine Category:Lente Category:Discontinued insulins